Offer up/FB Marketplace question

I got a place to put all my sets, been building and putting together everything fresh from boxes. But I am running out of projects, so I started searching. I found a 4483 AT-AT, sealed in box on marketplace, it's about $100 cheaper than online. Already suspicious, is there a way to purchase these and limit the risk? My first over thinking thought is they might be selling a box with bags of random parts in it, just resealed the box. Any advice? submitted by /u/dinkidonia [link] ...